The Tower House (castle) at Kildavnet, a late medieval tower house that was apparently built by the O’Malleys, stands on the shore of Achill Sound close to the southern tip of Achill Island. During July/August 2013, Achill Archaeological Field School undertook an excavation to the west of the tower house under Ministerial Consent, since the tower house is a National Monument in the guardianship of the State. The project investigated a 10m x 10m area and uncovered the foundation of a large wall, probably a late medieval bawn wall, which measured up to 1.4m wide and which appears to extend in a west-north-westerly direction from the south-western corner of the tower house. A bawn is a defended enclosure often constructed around a tower house in order to provide an outer defensive perimeter. The 1837 Ordnance Survey Map of Achill shows the tower sited in an enclosure but the later editions show a different arrangement of walls surrounding the tower house, associated with a late 19th century farmstead. Prior to the excavations it wasn’t clear if the earlier enclosing walls should be classified as a bawn or simply walls associated with an earlier 19th century cottage to the north west of the tower.
The wall appears to have been largely demolished in early modern times, but what survived was in good condition. There was some evidence to suggest that it was slightly narrower than the foundation upon which it rested, since external facade of the wall appears to have been set back from the face of the foundation, whereas the internal face of the wall rose directly from the face of the foundation below it. The foundation was composed of large blocks and boulders, measuring up to 70cm by 50cm, with smaller stones between them. Very few contemporary finds were uncovered, since the vast majority (over 99%) of artefacts came from early modern deposits associated with intensive spade-dug cultivation in the area, but a number of lower deposits contained significant amounts of animal-bone fragments and these may well contribute to our understanding of the site in the late medieval period. Little evidence was uncovered for structures within the bawn, since this area was only investigated in a narrow gap between the wall foundation and the edge of the trench. Proving the presence of a lost bawn enclosure was a very significant discovery.